1. Field of the Invention
The present invention relates to an optical-interference type reflective panel and a method for making the same, and more particularly to a reflective panel for which a supporting layer forming step is prior to a first conductive optical film stack forming step so as to simplify the manufacturing process of the reflective panel.
2. Description of Related Art
In order to minimize the bulky size of a computer display, the flat display was developed to replace the conventional CRT display. For example, the most well known flat display is the LCD. In recent years, different kinds of LCDs have been developed by display manufacturers. Most of these manufacturers are dedicated as far as possible to reduce the power consumption of the display so that the LCD will become more suitable for portable electronic products such as cell phones, PDAs and E-books.
Inside the LCD device, the back light module consumes the most power of all the elements. To solve the problem, a reflective type panel is developed, which utilizes the external light as the light source to replace the back light module.
Whether for the conventional LCD panel or the reflective type panel, a color filtering film and a polarizing film are constructed in the panel so as to display the color images and control the direction of the light. Even though these thin films are pervious to light, a partial amount of light may be blocked or lost while light passes through these films. To overcome the light loss problem, another reflective type panel called an optical-interference panel has accordingly been developed. Based on the interference phenomenon caused when light passes through different thin films, the aforementioned optical-interference panel is able to generate the fundamental red, blue and green colors by properly creating the thin film elements. Thus, the panel is able to show color images without the use of said color filter thin film and polarizing thin film, meanwhile the light transmittance of the panel is also improved so the panel is much more suitable to be applied to the portable electronic products.
With reference to FIG. 3, a single optical-interference regulator in the aforementioned optical-interference panel includes a substrate (70), a first conductive optical film stack (71) and a supporting layer (72) formed on the substrate (70). A second conductive optical film stack (73) (also called a mechanical layer) partly covers the adjacent supporting layers (72), whereby a gap is defined between the first and second conductive optical film stacks (71, 73).
When supplying an electrical field between the two conductive optical film stacks (71, 73) by an external driving circuit (not shown), the second conductive optical film stack (73) will be slightly deformed and becomes closer to the first conductive optical film stack (71). With the different gap distances between the two conductive optical film stacks (71,73), light beams passing through the panel will have different extents of interference, so that the panel is able to show different colors.
However, the fabricating process of the conventional panel is quite complex. With reference to FIGS. 4A and 4B, the first conductive optical film stack (71) and a spacing layer (701) are sequentially formed on the substrate (70) by well known film deposition, photolithography, film etching steps etc.
A negative photo-resist layer (not shown) is then applied on the surfaces of the first conductive optical film stack (71) and the spacing layer (701). With the steps of back-side exposing and photolithography, parts of the first conductive optical film stack (71) are removed from the substrate (70). The exposed regions of the substrate (70) are provided to form multiple supporting layers (72) thereon as shown in FIG. 4C.
With reference to FIG. 4D, the second conductive optical film stack (73) is formed on all supporting layers (72) and the spacing layer (701). In FIG. 4D, after removing the spacing layer (701) from the substrate (70), a gap is accordingly defined between the first and the second conductive optical film stacks (71)(73).
In the foregoing processes, since the first conductive optical film stack (71) is formed on the substrate (70) prior to the supporting layers (72), a precise self-alignment process (back-side exposing) is involved when applying the negative photo-resist layer on the first conductive optical film stack (71) and the spacing layer (701). Thus, the entire panel manufacturing process is particularly complex.
To mitigate and/or obviate the aforementioned problem, the present invention provides a novel optical-interference type reflective panel and a method for making the same.